Fuel mixer



Nov. 1, 1966 R. BAVERSTOCK FUEL MIXER 2 Sheets-Sheet 1 Filed Aug. 1, 1963 R. BAVERSTOCK FUEL MIXER Nov. 1, 1966 Filed Aug. 1, 1963 i EM 4/76 2 Sheets-Sheet 2 United States Patent 3,282,664 FUEL MIXER Richard Baverstock, North Long Beach, Calif., assignor to Imperial Machine Products Co., South Gate, Calif., a corporation of California Filed Aug. 1, 1963, Ser. No. 299,297 4 Claims. (Cl. 48-184) This invention relates to fuel mixers for internal combustion engines and is particularly directed to improvements over the mixer devices shown in my prior Patent No. 2,927,848, granted March 8, 1960, and in my prior Patent No. 3,123,451, granted March 3, 1964.

It is an important object of the present invention to provide an improved form of fuel mixer for internal combustion engines, which fuel mixer is adapted to mix atmospheric air with propane, butane, natural gas, or sewer gas, to serve as a combustible mixture for an internal combustion engine.

Another object is to provide a fuel mixer having substantially uniform radial flow of air to an axially movable air valve, in order to avoid uneven air flow around the periphery of the air valve.

Another object is to provide a device of this type in which the uniform radial air flow is accomplished by means of a stationary annular distribution ring.

Another object is to provide a device of this type in which the air valve is operated by a diaphragm and wherein the annular distribution ring assists in protecting the diaphragm against pressure developed by engine backfire.

Another object of this invention is to provide a stationary annular divider plate having relatively small clearance with an axially movable valve part and serving to afford major protection to the diaphragm against backfire pressure and further acting to produce a dashpot eflect on axial movement of the valve.

Another object is to provide a low-silhouette air-fuel mixer device in which a horizontal inlet pipe delivers air into a vertical mixer passage in substantially uniform flow.

Other and more detailed objects and advantages will appear hereinafter.

In the drawings:

FIGURE 1 is an axial sectional view showing a preferred embodiment of this invention.

FIGURE 2 is a top plan view partly broken away.

FIGURE 3 is a perspective view, showing the underside of the air valve.

FIGURE 4 is a perspective view, showing the upper portion of the air valve.

FIGURE 5 is a sectional elevation taken substantially on the lines 55 as shown in FIGURE 1.

FIGURE 6 is a sectional plan view taken substantially on the lines 66 as shown in FIGURE 1.

FIGURE 7 is a sectional detail taken substantially on the lines 77 as shown in FIGURE 6.

FIGURE 8 is a sectional detail taken substantially on the lines 88 as shown in FIGURE 1.

FIGURE 9 is an inverted plan view, partly broken away, taken substantially in the direction of the lines 99 as shown in FIGURE 1.

Referring to the drawings, a housing generally designated 10 is attached to the open upper end of flanged tubular member 11, containing a conventional throttle valve 12. The flange 13 on the lower end of the tubular member 11 is provided with apertures 14 for securing the device to the inlet manifold, not shown, of an internal combustion engine.

The housing 10 is provided with an upstanding circular inner wall 16 encircled by a concentric outstanding circular outer wall 17. The outer wall 17 is provided with a radially extending tubular part 18, which provides a 3,282,664 Patented Nov. 1, 1966 horizontal inlet pipe for air and which communicates with the generally annular space 19 defined between the concentric walls 16 and 17. The bottom of this space 19 is defined by the bottom wall 20. The housing 10 also includes a tubular part 22, extending between the walls 16 and 17 adjacent the bottom wall 20 and serving as a radial inlet 23 for gaseous fuel. A restrictor 24 limits the flow of gaseous fuel through the inlet 23. A conduit 26 formed on the housing 10 has a central opening 25 communicating with the inlet 23. This conduit extends radially inward from the inner Wall 16 and is provided with a central upstanding stationary hollow post 27.

In the general plan of operation, the combined air valve and fuel valve assembly generally designated 30 moves axially in response to the rate of flow of air from the horizontal inlet 31 into the upper end of the discharge passage 32 defined within the inner wall 16. The assembly 30 acts to regulate the flow of gaseous fuel from the inlet 23 into the passage 32. The combined air valve and fuel valve assembly 30 includes an air valve member 33 having an axial cylindrical portion 34 provided with an outward flaring portion 35 at its upper end. The air valve member 33 has a central cylindrical bore 36, which slidably receives the outward projecting axial ribs 29 on the upstanding hollow post 27 The air valve member 33 is also provided with a plurality of circumferentially spaced axially extending tubes 37 formed integrally therewith and having passages 38 extending completely through the air valve member 33. Radial fins 39 are formed integrally on the air valve member and project radially outward beyond the circular edge of the flaring portion 35. The upper ends of the projecting portions of the fins 39 are coplanar with an upward-facing shoulder 40 provided on the upper end of the air valve member 33. A loose ring 41 rests on this shoulder 40 and is adapted to engage the air-valve seat 42 provided at the upper end of the circular wall 16. The action of the floating ring 41 is such as to allow fuel-valve element to come to fully closed position after the ring 41 has engaged the seat.

An annular spacer 45 having a cylindrical outer surface 46 is centrally attached to the upper end of the air-valve member 33 and functions as a part thereof. The spacer 45 has a downward-facing shoulder 47 which overlies a portion of the ring 41, but which is spaced from the shoulder 40 to allow limited axial movement of the ring 41 with respect to the air-valve member 33.

The fule-valve element 50 is mounted concentrically within the cylindrical bore 36 of the air-valve member 33, and upward-projecting stem 51 on the fuel-valve element 50 projects through central aligned apertures in the air-valve member 33 and bottom flange 52 of the spacer 45. The stem 51 also projects through resilient seat washer 49 and through a washer 53 for centering the spring 62. The upper end of the stem 51 is deformed to prevent disassembly of the parts 33, 45, 49, and 53. The outer surface 54 of the fuel-valve element 50 is shaped to cooperate with the axial cylindrical bore 55 in the upstanding post 27, to regulate the flow of gaseous fuel upward through the bore 55 and into the interior bore 36 of the air-valve member 33. The air-valve member 33 and the fuel-valve element 50 move up and down as a unit under axial force applied by the annular diaphragm 56 and the compression spring 62. The outer peripheral edge of the diaphragm 56 is clamped between the cover plate 57 and the housing extension 58, and the latter parts are secured to the housing 10 by means of the threaded fastenings 59. The inner portion of the diaphragm 56 is clamped between a backup plate 60 and the upper end of the spacer 45 by means of threaded fastenings 61. The space 63 above the diaphragm 56 communicates with the discharge passage 32 by way of the central openings in the backup plate 60, diaphragm 56, and spacer 45, and through the apertures 64 in the bottom flange 52 and through openings 38. Accordingly, the space 63 above the diaphragm is subjected to pressure in the discharge passage 32 downstream from the combined air valve and fuel valve assembly 30.

A horizontal divider plate 70 is annular in shape and is formed as a part of the housing extension 58. This divider plate 70 defines the upper boundary of the space 19. It has a central opening 71 slightly larger than the outer cylindrical surface 46 of the spacer 45. Accordingly, when the parts are at rest, the pressure in the space 72 below the diaphragm 56 is the same as the pressure in the upper part of the space 19.

When the pressure in the space 72 below the diaphragm 56 exceeds the pressure above the diaphragm 56 in the space 63 by a predetermined amount, the combined air valve and fuel valve assembly 30 moves upward in a direction to compress the spring 62. This action lifts the loose ring 41 upward away from the seat 42 to allow air to flow radially over the seat 42 and into the discharge passage 32. The same lifting motion of the fuelvalve element 50 serves to increase the flow of gaseous fuel upward through the bore 55 and then radially over the upper end of the upstanding post 27 and into the discharge passage 32.

For optimum mixing of gaseous fuel and air in the proper ratio throughout the range of operation, it is important to minimize vortex action or swirling of either air or gaseous fuel. It has been found that superior results are achieved by the use of the stationary air distributor ring 75, which is mounted on the inner circular wall 16 just below the air-valve seat 42, This distributor ring 75 extends radially int-o the space 19 to divide the space 19 into an upper chamber 76 and a lower chamber 77. In practice, the area of the annular space 78 between the outer rim of the distributor ring 75 and the inner surface of the wall 17 is made substantially equal to the cross-section area of the inside diameter of the inlet pipe 31. The major portion of the volume of air entering the air inlet pipe 31 passes into the lower chamber 77. The air then flows into the upper chamber 76 and radially over the distributor ring 75. The air then flows over the seat 42 and into the upper end of the discharge passage 32 with a minimum of swirl or vortex action. The radial fins 39 on the airvalve member 33 insure axial air flow with minimum swirling, and the radial ribs 29 on the hollow stationary post 27 insure axial flow of gaseous'fuel with minimum swirling. The fuel and air mix within the discharge passage 32 immediately below the air-valve member 33.

The distributor ring 75 has an additional function of helping to minimize damaging back pressures on the diaphragm 56 in the event of engine backfiring. The major portion of this protection, however, is achieved by means of the divider plate '70 and its restricted passage 71 with the outer surface 46 of the spacer 45. The restricted passage 71 provides for dashpot action, limiting rapid axial movement of the combined air valve and fuel valve assembly 30.

The distributor ring 75 also enables the air-fuel mixer device to have a minimum overall height, or low silhouette, without reducing the vertical length of the mixing passage 32. The major portion of the horizontal air-inlet pipe 31 lies below the level of the distributor ring 75. The air is thus caused to turn a 90 corner but retains substantially uniform flow into and around the upper end of the mixing passage 31.

Means are provided for adjusting the richness of the air-fuel mixture, and, as shown in the drawings, this means includes the restrictor 24, which is mounted in the fuel inlet 23. As best shown in FIGURES 1, 7, and 8, the restrictor 24 includes a central vane 80, which extends between circular hubs 81 and 82, mounted to turn in recesses provided on the tubular part 22. The vane 80 extends across the fuel inlet passage 23. The restrictor 24 is maintained in position by means of a washer 83 and a retainer 84. An exposed head 85 is provided with french flats 86, and a scale 87 may be provided on the underside of the member 22 for convenience. The restrictor 24 may be turned to change the angular position of the vane 80 within the fuel-inlet passage 23, and thereby change the degrees of restriction to flow. This has the effect of changing the ratio of fuel to air and hence provides an adjustment for maximum power. This adjustment is principally effective at peak loads and is less effective for lower loads.

Additional means are provided for adjusting the richness of the fuel mixture at idle speed, and, as best shown in FIGURE 6 of the drawings, this means takes the form of a bore 90 extending through the wall 16 to establish communication between the space 19 and the discharge passage 32. A machine screw 91 threaded in the housing passes through a pocket 92 and coil spring 93, and this machine screw may be turned to restrict the bore 90 to any desired extent. Maxi-mum richness of mixture is achieved when the restriction is greatest. When the port 90 is fully or partly opened, the airvalve member 33 is not measuring all of the air moving through the mixer, and hence it closes slightly, and, in so doing, reduces the amount of gaseous fuel fed into the mixture by closing the gas port slightly. No extra air flows through the mixer, but less gaseous fuel flows through the fuel valve. This adjustment has little effect on air-fuel mixtures at any flow other than at idle speed.

Vortex-preventing ribs 94 are mounted within the space 19 on opposite sides of the restrictor 24 and assist in preventing vortex action of air in the space 19. The upper edges of these ribs 94 terminate below the level of the seat 42.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details set forth above, but my invention is of the full scope of the appended claims.

I claim:

1. In an air-fuel mixer device, the combination of: a housing having concentric inner and outer walls defining a space therebetween, the inner wall defining an axial discharge passage centrally therein, a distributor ring secured on said inner wall and extending radially into said space to divide it .into a -first chamber and a second chamber, the outer wall having a lateral air inlet pipe positioned to deliver air primarily int-o said second chamber, the inner wall having a seat at one end in communication with said first chamber and positioned to receive air flowing radially inward from said first chamber, said distributor ring serving to minimize vortex action of air entering through said seat, an air valve member mounted for axial movement in the housing toward and away from the seat, a fuel valve element fixed concentrically within the air valve member and movable as a unit therewith, a fuel supply conduit having an axial opening cooperating with said fuel valve element to control flow of fuel into said discharge passage, and means for axially moving the air valve member and the fuel valve element.

2. In an air-fuel mixer device, the combination of: a housing having upstanding concentric inner and outer walls defining a space therebetween, the inner wall defining an axial discharge passage centrally therein, a horizontal distributor ring secured on said inner wall and extending radially int-o said space to divide it into an upper chamber and a lower chamber, the outer wall having a horizontal air inlet pipe positioned to deliver air primarily into said [lower chamber, the inner wall having a seat at its upper end in communication with said upper chamber and positioned to receive ai-r flowing radially inward from said upper chamber, said distributor ring serving to minimize vortex action of air entering through said seat, an air valve member mounted for axial vertical movement in the housing toward and away from the seat, a fuel valve element fixed concentrically within the air valve member and movable as a unit therewith, a fuel supply conduit having an axial opening cooperating with said fuel valve element to control flow of fuel into said discharge passage, and means for axially moving the air valve member and the fuel valve element.

3. In an air-fuel mixer device, the combination of: a housing having concentric inner and outer walls defining a space therebetween, the inner Wall defining an axial discharge passage centrally therein, a distributor ring secured on said inner wall and extending radially into said space to divide it into a first chamber and a second chamber, the outer wall having a lateral air inlet pipe positioned to deliver air primarily into said second chamber, the inner wall having a seat at one end in communication with said first chamber and positioned to receive air flowing radial-1y inward from said first chamber, said distributor ring serving to minimize vor-tex action of air entering through said seat, an air valve member mounted for axial movement in the housing toward and away from the seat, a divider plate on the housing forming one wall of said first chamber and having a central opening therein, a portion of said air valve member passing through said central opening with small clearance to form a restricted passage, a fuel valve element fixed concentrically within the air valve member and movable as a unit therewith, a fuel supply conduit having an axial opening cooperating with said fuel valve element to control flow of fuel into said discharge passage, and means for axially moving the air valve member and the fuel valve element.

4. In an air-fuel mixer device, the combination of: a housing having concentric inner and outer walls defining a space therebetween, the inner wall defining an axial discharge passage centrally therein and having a seat at one end of said wall, the outer wall having a lateral air inlet pipe positioned to deliver air primarily into said space, an air valve member mounted for axial movement in the housing toward and away from the seat, a divider plate on the housing forming one wall of said space and having a central opening therein, a :portion of said air valve member passing through said central opening with small clearance to form a restricted passage, 21 fuel valve element fixed concentrically within the air valve member and movable as a unit therewith, a fuel supply conduit having an axial opening cooperating with said fuel valve element to control flow of fuel into said discharge passage, and means for axially moving the air valve member and the fuel valve element.

References Cited by the Examiner UNITED STATES PATENTS 1,013,214 1/1912 Noyes 48184 2,927,848 3/1960 Baverstock 48-184 3,123,451 3/1964 Baverstock 48-184 MORRIS O. WOLK, Primary Examiner.

J. SC'OVRONEK, Assistant Examiner. 

1. IN AN AIR-FUEL MIXER DEVICE, THE COMBINATION OF: A HOUSING HAVING CONCENTRIC INNER AND OUTER WALLS DEFINING A SPACE THEREBETWEEN, THE INNER WALL DEFINING AN AXIAL DISCHARGE PASSAGE CENTRALLY THEREIN, A DISTRIBUTOR RING SECURED ON SAD INNER WALL AND EXTENDING RADIALLY INTO SAID SPACE TO DIVIDE IT INTO A FIRST CHAMBER AND A SECOND CHAMBER, THE OUTER WALL HAVING A LATERAL AIR INLET PIPE POSITIONED TO DELIVER AIR PRIMARILY INTO SAID SECOND CHAMBER, THE INNER WALL HAVING A SEAT AT ONE END IN COMMUNICATION WITH SAID FIRST CHAMBER AND POSITIONED TO RECEIVE AIR FLOW ING RADIALLY INWARD FROM SAID FIRST CHAMBER, SAID DISTRIBUTOR RING SERVING TO MINIMIZE VORTEX ACTION OF AIR ENTERING THROUGH SAID SEAT, AN AIR VALVE MEMBER MOUNTED FOR AXIAL MOVEMENT IN THE HOUSING TOWARD AND AWAY FROM THE SEAT, A FUEL VALVE ELEMENT FIXED CONCENTRICALLY WITHIN THE AIR VALVE MEMBER AND MOVABLE AS A UNIT THEREWITH, A FUEL 